1. Technical Field
This invention relates generally to medical equipment, and more particularly to a blood oxygenation system.
2. Background Information
A blood oxygenation system serves as the patient's lungs during such procedures as open heart surgery. It includes an oxygenation module or oxygenator that replaces carbon dioxide in the blood with a fresh supply of oxygen and a separate heat exchanger that regulates blood temperature. Thus, it is an important component in various surgical procedures and the details of design demand attention.
Some oxygenators employ a bundle of hollow fibers as conduits for a flow of oxygen. They are formed from microporous membrane material and as a result some of the oxygen flows through the pores to blood pumped past the fiber exteriors while carbon dioxide from the blood flows in the opposite direction to join the flow of oxygen as it is vented. That process oxygenates the blood, and the membrane oxygenator described in U.S. patent application Ser. No. 056,135 filed May 29, 1987 provides an example.
Similarly, the heat exchanger may employ a heat exchange coil as a conduit for a flow of temperature regulated water. As the blood flows past the exterior surface of the heat exchange coil, heat transfers through the coil between the blood and the water to regulate blood temperature. The heat exchanger described in Raible U.S. Pat. No. 4,428,934 is an example and that patent is incorporated for the details provided.
There are certain drawbacks with existing membrane oxygenation systems, however, such as the priming volume that the system requires as well as the efficiency of the oxygen and carbon dioxide exchange accompanying the use of separate heat exchange and oxygenation modules and the relatively inefficient membrane gas exchange modules. Those things can, in turn, result in a larger system with higher priming volumes and fabrication costs, and the need for higher pumping pressure with the attendant risk of blood damage. Consequently, it is desirable to have an oxygenation system that alleviates those concerns.